1/* DWARF2 EH unwinding support for S/390 Linux. 2 Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify it under 7the terms of the GNU General Public License as published by the Free 8Software Foundation; either version 2, or (at your option) any later 9version. 10 11In addition to the permissions in the GNU General Public License, the 12Free Software Foundation gives you unlimited permission to link the 13compiled version of this file with other programs, and to distribute 14those programs without any restriction coming from the use of this 15file. (The General Public License restrictions do apply in other 16respects; for example, they cover modification of the file, and 17distribution when not linked into another program.) 18 19GCC is distributed in the hope that it will be useful, but WITHOUT ANY 20WARRANTY; without even the implied warranty of MERCHANTABILITY or 21FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 22for more details. 23 24You should have received a copy of the GNU General Public License 25along with GCC; see the file COPYING. If not, write to the Free 26Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2702110-1301, USA. */ 28 29/* Do code reading to identify a signal frame, and set the frame 30 state data appropriately. See unwind-dw2.c for the structs. */ 31 32#define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state 33 34static _Unwind_Reason_Code 35s390_fallback_frame_state (struct _Unwind_Context *context, 36 _Unwind_FrameState *fs) 37{ 38 unsigned char *pc = context->ra; 39 long new_cfa; 40 int i; 41 42 typedef struct 43 { 44 unsigned long psw_mask; 45 unsigned long psw_addr; 46 unsigned long gprs[16]; 47 unsigned int acrs[16]; 48 unsigned int fpc; 49 unsigned int __pad; 50 double fprs[16]; 51 } __attribute__ ((__aligned__ (8))) sigregs_; 52 53 sigregs_ *regs; 54 int *signo; 55 56 /* svc $__NR_sigreturn or svc $__NR_rt_sigreturn */ 57 if (pc[0] != 0x0a || (pc[1] != 119 && pc[1] != 173)) 58 return _URC_END_OF_STACK; 59 60 /* Legacy frames: 61 old signal mask (8 bytes) 62 pointer to sigregs (8 bytes) - points always to next location 63 sigregs 64 retcode 65 This frame layout was used on kernels < 2.6.9 for non-RT frames, 66 and on kernels < 2.4.13 for RT frames as well. Note that we need 67 to look at RA to detect this layout -- this means that if you use 68 sa_restorer to install a different signal restorer on a legacy 69 kernel, unwinding from signal frames will not work. */ 70 if (context->ra == context->cfa + 16 + sizeof (sigregs_)) 71 { 72 regs = (sigregs_ *)(context->cfa + 16); 73 signo = NULL; 74 } 75 76 /* New-style RT frame: 77 retcode + alignment (8 bytes) 78 siginfo (128 bytes) 79 ucontext (contains sigregs) */ 80 else if (pc[1] == 173 /* __NR_rt_sigreturn */) 81 { 82 struct ucontext_ 83 { 84 unsigned long uc_flags; 85 struct ucontext_ *uc_link; 86 unsigned long uc_stack[3]; 87 sigregs_ uc_mcontext; 88 } *uc = context->cfa + 8 + 128; 89 90 regs = &uc->uc_mcontext; 91 signo = context->cfa + sizeof(long); 92 } 93 94 /* New-style non-RT frame: 95 old signal mask (8 bytes) 96 pointer to sigregs (followed by signal number) */ 97 else 98 { 99 regs = *(sigregs_ **)(context->cfa + 8); 100 signo = (int *)(regs + 1); 101 } 102 103 new_cfa = regs->gprs[15] + 16*sizeof(long) + 32; 104 fs->cfa_how = CFA_REG_OFFSET; 105 fs->cfa_reg = 15; 106 fs->cfa_offset = 107 new_cfa - (long) context->cfa + 16*sizeof(long) + 32; 108 109 for (i = 0; i < 16; i++) 110 { 111 fs->regs.reg[i].how = REG_SAVED_OFFSET; 112 fs->regs.reg[i].loc.offset = 113 (long)®s->gprs[i] - new_cfa; 114 } 115 for (i = 0; i < 16; i++) 116 { 117 fs->regs.reg[16+i].how = REG_SAVED_OFFSET; 118 fs->regs.reg[16+i].loc.offset = 119 (long)®s->fprs[i] - new_cfa; 120 } 121 122 /* Load return addr from PSW into dummy register 32. */ 123 124 fs->regs.reg[32].how = REG_SAVED_OFFSET; 125 fs->regs.reg[32].loc.offset = (long)®s->psw_addr - new_cfa; 126 fs->retaddr_column = 32; 127 /* SIGILL, SIGFPE and SIGTRAP are delivered with psw_addr 128 after the faulting instruction rather than before it. 129 Don't set FS->signal_frame in that case. */ 130 if (!signo || (*signo != 4 && *signo != 5 && *signo != 8)) 131 fs->signal_frame = 1; 132 133 return _URC_NO_REASON; 134} 135